UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(D) OF

THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): September 15, 2026

GREENE COUNTY BANCORP, INC.

(Exact Name of Registrant as Specified in its Charter)

United States of America	0-25165	14-1809721
(State or Other Jurisdiction of Incorporation)	(Commission File No.)	(I.R.S. Employer Identification No.)

302 Main Street, Catskill NY	12414
(Address of Principal Executive Offices)	(Zip Code)

Registrant’s telephone number, including area code: (518) 943-2600

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐
Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐
Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of class	Trading symbol	Name of exchange on which registered Common
Common Stock, $0.10 par value	GCBC	The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01 Other Events

On September 15, 2026, Greene County Bancorp, Inc. (the “Company”) redeemed $10.0 million in aggregate principal amount of its outstanding 3.00% Fixed-to-Floating Rate Subordinated Notes due September 15, 2031 (the “Notes”). The redemption price was equal to 100% of the principal amount redeemed, plus accrued and unpaid interest thereon to, but excluding, September 15, 2026. Following the redemption, $20.0 million in aggregate principal amount of the Notes remains outstanding. The Company funded the redemption with cash on hand.

Item 9.01 Financial Statements and Exhibits

Exhibit No.	Description
104	Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, hereunto duly authorized.

	GREENE COUNTY BANCORP, INC.
DATE: September 15, 2026	By:	/s/ Donald E. Gibson
	Donald E. Gibson
	President & Chief Executive Officer